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Added Box and Gaussian blurring

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nobytesgiven 2022-10-23 22:54:49 +03:00
parent 483f10397e
commit 1f4f26e7b0
2 changed files with 147 additions and 0 deletions
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2
src/raylib.h
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@ -1258,6 +1258,8 @@ RLAPI void ImageAlphaCrop(Image *image, float threshold);
RLAPI void ImageAlphaClear(Image *image, Color color, float threshold); // Clear alpha channel to desired color
RLAPI void ImageAlphaMask(Image *image, Image alphaMask); // Apply alpha mask to image
RLAPI void ImageAlphaPremultiply(Image *image); // Premultiply alpha channel
RLAPI void ImageBlurBox(Image *image, int blurSize); // Apply box blur
RLAPI void ImageBlurGaussian(Image *image, int blurSize); // Apply Gaussian blur using a box blur approximation
RLAPI void ImageResize(Image *image, int newWidth, int newHeight); // Resize image (Bicubic scaling algorithm)
RLAPI void ImageResizeNN(Image *image, int newWidth,int newHeight); // Resize image (Nearest-Neighbor scaling algorithm)
RLAPI void ImageResizeCanvas(Image *image, int newWidth, int newHeight, int offsetX, int offsetY, Color fill); // Resize canvas and fill with color

145
src/rtextures.c
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@ -194,6 +194,10 @@
#define PIXELFORMAT_UNCOMPRESSED_R5G5B5A1_ALPHA_THRESHOLD 50 // Threshold over 255 to set alpha as 0
#endif
#ifndef GAUSSIAN_BLUR_ITERATIONS
#define GAUSSIAN_BLUR_ITERATIONS 4 // Number of box blur iterations to approximate gaussian blur
#endif
//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------
@ -1494,6 +1498,147 @@ void ImageAlphaPremultiply(Image *image)
ImageFormat(image, format);
}
// Apply box blur
void ImageBlurBox(Image *image, int blurSize) {
// Security check to avoid program crash
if ((image->data == NULL) || (image->width == 0) || (image->height == 0)) return;
ImageAlphaPremultiply(image);
Color *pixels = LoadImageColors(*image);
Color *pixelsCopy = LoadImageColors(*image);
// Horizontal box blur
for (int row = 0; row < image->height; row++)
{
float avgR = 0.0f;
float avgG = 0.0f;
float avgB = 0.0f;
float avgAlpha = 0.0f;
int convolutionSize = blurSize+1;
for (int i = 0; i < blurSize+1; i++)
{
avgR += pixelsCopy[row*image->width + i].r;
avgG += pixelsCopy[row*image->width + i].g;
avgB += pixelsCopy[row*image->width + i].b;
avgAlpha += pixelsCopy[row*image->width + i].a;
}
pixels[row*image->width].r = (unsigned char) (avgR/convolutionSize);
pixels[row*image->width].g = (unsigned char) (avgG/convolutionSize);
pixels[row*image->width].b = (unsigned char) (avgB/convolutionSize);
pixels[row*image->width].a = (unsigned char) (avgAlpha/convolutionSize);
for (int x = 1; x < image->width; x++)
{
if (x-blurSize >= 0)
{
avgR -= pixelsCopy[row*image->width + x-blurSize].r;
avgG -= pixelsCopy[row*image->width + x-blurSize].g;
avgB -= pixelsCopy[row*image->width + x-blurSize].b;
avgAlpha -= pixelsCopy[row*image->width + x-blurSize].a;
convolutionSize--;
}
if (x+blurSize < image->width)
{
avgR += pixelsCopy[row*image->width + x+blurSize].r;
avgG += pixelsCopy[row*image->width + x+blurSize].g;
avgB += pixelsCopy[row*image->width + x+blurSize].b;
avgAlpha += pixelsCopy[row*image->width + x+blurSize].a;
convolutionSize++;
}
pixels[row*image->width + x].r = (unsigned char) (avgR/convolutionSize);
pixels[row*image->width + x].g = (unsigned char) (avgG/convolutionSize);
pixels[row*image->width + x].b = (unsigned char) (avgB/convolutionSize);
pixels[row*image->width + x].a = (unsigned char) (avgAlpha/convolutionSize);
}
}
// Vertical box blur
for (int col = 0; col < image->width; col++)
{
float avgR = 0.0f;
float avgG = 0.0f;
float avgB = 0.0f;
float avgAlpha = 0.0f;
int convolutionSize = blurSize+1;
for (int i = 0; i < blurSize+1; i++)
{
avgR += pixels[i*image->width + col].r;
avgG += pixels[i*image->width + col].g;
avgB += pixels[i*image->width + col].b;
avgAlpha += pixels[i*image->width + col].a;
}
pixelsCopy[col].r = (unsigned char) (avgR/convolutionSize);
pixelsCopy[col].g = (unsigned char) (avgG/convolutionSize);
pixelsCopy[col].b = (unsigned char) (avgB/convolutionSize);
pixelsCopy[col].a = (unsigned char) (avgAlpha/convolutionSize);
for (int y = 1; y < image->height; y++)
{
if (y-blurSize >= 0)
{
avgR -= pixels[(y-blurSize)*image->width + col].r;
avgG -= pixels[(y-blurSize)*image->width + col].g;
avgB -= pixels[(y-blurSize)*image->width + col].b;
avgAlpha -= pixels[(y-blurSize)*image->width + col].a;
convolutionSize--;
}
if (y+blurSize < image->height)
{
avgR += pixels[(y+blurSize)*image->width + col].r;
avgG += pixels[(y+blurSize)*image->width + col].g;
avgB += pixels[(y+blurSize)*image->width + col].b;
avgAlpha += pixels[(y+blurSize)*image->width + col].a;
convolutionSize++;
}
pixelsCopy[y*image->width + col].r = (unsigned char) (avgR/convolutionSize);
pixelsCopy[y*image->width + col].g = (unsigned char) (avgG/convolutionSize);
pixelsCopy[y*image->width + col].b = (unsigned char) (avgB/convolutionSize);
pixelsCopy[y*image->width + col].a = (unsigned char) (avgAlpha/convolutionSize);
}
}
// Reverse premultiply
for (int i = 0; i < image->width*image->height; i++)
{
if (pixelsCopy[i].a == 0)
{
pixelsCopy[i].r = 0;
pixelsCopy[i].g = 0;
pixelsCopy[i].b = 0;
}
else if (pixelsCopy[i].a < 255)
{
float alpha = (float)pixelsCopy[i].a/255.0f;
pixelsCopy[i].r = (unsigned char)((float)pixelsCopy[i].r/alpha);
pixelsCopy[i].g = (unsigned char)((float)pixelsCopy[i].g/alpha);
pixelsCopy[i].b = (unsigned char)((float)pixelsCopy[i].b/alpha);
}
}
int format = image->format;
RL_FREE(image->data);
UnloadImageColors(pixels);
image->data = pixelsCopy;
image->format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8;
ImageFormat(image, format);
}
void ImageBlurGaussian(Image *image, int blurSize)
{
for (int i = 0; i < GAUSSIAN_BLUR_ITERATIONS; i++) ImageBlurBox(image, blurSize);
}
// Resize and image to new size
// NOTE: Uses stb default scaling filters (both bicubic):
// STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM